Our research objectives are to investigate the metabolism and metabolic control of wound healing in relation to aging. One of the common features in healing systems we found in previous studies is a metabolic adaptation of injured tissues to the altered cellular environment. Wound healing is delayed in older individuals. We propose the mechanism of "natural delay" of wound healing in aged skin to be a derangement of energy metabolism. This research proposal includes the investigation of enzyme activities and energy metabolism in the regenerating epithelium and granulation tissues during would healing of young versus aged skin of Fischer 344 rats. Cyclic nucleotide system will be investigated to elucidate its possible involvement of metabolic control in wounds. Microanalytical techniques are essential to the metabolic investigation in isolated regenerating (or migrating) epithelium) and granulation tissue. We will attempt to establish computer simulation and mathematical modelling of metabolic events in wound healing and aging on the basis of our experimental results.